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# SHM and hooke's law HELP!!!!! watch

1. This question is really confusing me

Using your knowledge of Hooke's law and Newton's second law determine the period T of a trolley moving in Simple Harmonic Motion in terms of the force constant k and the mass m of the trolley

I did
-kx = ma

a = -(2pief)^2 x
therefore -kx = m[-(2pief)^2 x]
minuses and x cancel
so k= m[2pie(1/T)]^2
k = 4pie^2m/T^2
T^2 = 4pie^2m/k
T = 2pie root(m/k)

but the answer is T = 2pie root(k/m)

2. Any1??
3. is this at A level?
4. (Original post by alithegreat)
This question is really confusing me

Using your knowledge of Hooke's law and Newton's second law determine the period T of a trolley moving in Simple Harmonic Motion in terms of the force constant k and the mass m of the trolley

I did
-kx = ma

a = -(2pief)^2 x
therefore -kx = m[-(2pief)^2 x]
minuses and x cancel
so k= m[2pie(1/T)]^2
k = 4pie^2m/T^2
T^2 = 4pie^2m/k
T = 2pie root(m/k)

but the answer is T = 2pie root(k/m)

F = (-) kx and F = ma
Therefore ma = (-) kx
ω2 = k /m
T = 2π (m/ k)

so the answer is right, must be some error on your books end

edit - this is from a specimen paper for physics i copy and pasted

Take a look for it yourself.
5. You didn't do anything wrong. Your answer is correct, the answer given to you is wrong. The period of a mass attached to a helical spring doing SHM is T=2pie x root(m/K). Its a formula often given in textbooks and formula booklets.
6. thnx guys i guess the ms is wrong

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